The invention relates to vibration damping apparatus in general, and more particularly to improvements in vibration damping apparatus which can be utilized with advantage in or ahead of power trains between the engines and wheels of motor vehicles. Vibration damping apparatus of the type to which the present invention pertains are disclosed in numerous United States and foreign patents as well as in numerous pending United States and foreign patent applications of the assignee of the present application. Reference may be had, for example, to U.S. Pat. Nos. 4,611,701, 4,739,866 and 4,890,710.
Vibration damping apparatus which are installed between the output element of an engine and a power train in a motor vehicle normally comprise an input member (such as a first rotary flywheel which is driven by the crankshaft of the engine), an output member (such as a second flywheel which is connectable with the power train, e.g., by way of an engageable and disengageable friction clutch, and is coaxial with and rotatable relative to the first flywheel), and a damping device which operates between the input and output members. As a rule, the damping device comprises energy storing means including springs which yieldably oppose angular movements of the input and output members relative to each other.